OK, so the problem in the UK is that although you are allowed to begin a journey with BG at 5mmol, you have to take on carb by law if your BG is under this - now, if my BG is 4.9 for example and I take on even 1 jelly baby, it's going to be about 7.5 mmol within 10 minutes even though I can guarantee that with no bolus available and 20 hours since my last basal, the only place my BG is going on my drive home from work is up - the law does not allow for your knowledge, judgement etc - it basically says I have to destroy my health to be allowed to drive. It further says that if your BG is under 4.5 mmol (or that might be 4, can't quite remember), you must eat something and wait until it is above 5mmol before driving. If you treat a hypo, you must not drive for 45 minutes after your BG has come back above 5mmol. You must test within 2 hours before the start of your journey and every two hours during your journey - the above rules apply throughout your journey.
It's all absolute rubbish, but it is the law. If you have an accident, regardless of whether it is your fault, the police can and will take your BG tester. if you have not tested before starting your journey, or if your BG wasn't within limits, you can be prosecuted and you will lose your license. Your license states that you are insulin-dependent, so the police do not have to know you are diabetic - they just have to run a driver check which is standard practice at an accident - and they will ask for your meter and check.
Given all of that, I really don't see how anyone who drives even twice a day to and from work can get an HbA1c below 5.4 or 5.5 and legally drive.
Smidge